Conditionals ("If") and definitions for 3D plots
- To: mathgroup at smc.vnet.net
- Subject: [mg14094] Conditionals ("If") and definitions for 3D plots
- From: "Julio Vera" <lvera at varela.reu.edu.uy>
- Date: Fri, 25 Sep 1998 03:15:20 -0400
- Sender: owner-wri-mathgroup at wolfram.com
Hello. This is my first posting to the list. I'm very new to
Mathematica. I have studied quite a bit of The Mathematica Book in the last 2 weeks,
though.
A few questions.
1) How to give NO value to the "else" parameter of the function
If[expr, then, else]
I want a function to be defined ONLY if the condition is true. I tried
to leave a blank, a space, and to put the "not exist" symbol, with no
luck.
I tried the "Which" function too.
2) How to define a dominium range (for a function to be plotted) by
means of an equation
Instead of giving a maximum and a minimum value to the variables
involved (by expressions like {x,-1,1},{y,-1,1}), use a function, maybe
an implicit one like 4x^2+y^2==1 .
3) ImplicitPlot3D
For Plot, we have Plot3D. Same thing with ParametricPlot and
ParametricPlot3D. But I cannot find an equivalent tridimensional
function to ImplicitPlot. I have used the normal Mathematica functions, and
those in the Graphics' package.
Thanks for your help and your time.
Julio Vera